Question

我有一个显示结果的数组如下：

Array
(
    [0] => 71
    [1] => 56
    [2] => 64
    [3] => 82
    [4] => 90
    [5] => 80
    [6] => 65
    [7] => 62
    [8] => 14
    [9] => 3
)

我的代码是：

while($row = mysql_fetch_assoc($result))
{   

  $show[] = $row['number'];

}
   echo '<pre>'; print_r($show);

如何随机化数组内容并将其显示为仅5位数e：g 71 64 14 80 82

Answer 1

$rand5 = array_rand(array_flip($show), 5);
// we need array_flip because array_rand returns the keys

http://php.net/array_rand

http://php.net/array_flip

Answer 2

我会用shuffle来随机化数组，因为获取数组的5个元素，这实际上取决于你的需要，你想要完成什么，得到前5个元素，最后一些，或其他一些逻辑。

Answer 3

试试这个：

$arr=array();
for ($i=0;$i<5;$i++)
{
$arr[i]=$items[array_rand($items)];
}

$arr包含结果

Answer 4

在查询中不确定是否有这个，但您也可以使用

SELECT number
FROM SomeTable
ORDER BY RAND()
LIMIT 5

但请注意，ORDER BY RAND（）效率非常低，因此仅在处理少量行时才适用。但是，如果要返回大量行，那么在PHP中执行它也会效率低下。

有更有效的方法可以返回单个随机行，因此如果您有非常多的行，则可以使用5次有效检索单行并将结果合并在一起（尽管您需要考虑到随机行可能是重复的可能性。

例如（并不是很满意）： -

(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
UNION
(SELECT r1.number
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND( ) * ( MAX( number ) - MIN( number ) ) + MIN( number ) AS number
    FROM SomeTable
) AS r2
ON r1.number >= r2.number
ORDER BY r1.number ASC
LIMIT 1)
LIMIT 5

SQL小提琴： -

http://sqlfiddle.com/#!2/14caa/4

这将获得10个随机行，然后使用另一个LIMIT 5来获得仅5行。当然，这可能不会得到5行的可能性很小（不太可能，但是这些联合查询中的每一个都可能会返回同一行）

显示和随机化PHP阵列

4 个答案: